Stimuli and Responses- Control of Heart Rate Flashcards
Where does the process of controlling heart rate start?
In the sinoatrial node in the wall of the right atrium
How is the SAN a pacemaker?
It sets the rhythm of the heartbeat by sending out regular waves of electrical activity to the atrial walls
What is caused by the SAN acting as a pacemaker?
The right and left atria to contract at the same time
What does a band of non-conducting collagen tissue do?
Prevents the waves of electrical activity from being passed directly from the atria to the ventricles
Where are the waves of electrical activity transferred to from the SAN?
To the atrioventricular node
What is the AVN responsible for?
For passing the waves of electrical activity onto the bundle of His
Why is there a slight delay before the AVN reacts?
To make sure the atria have emptied before the ventricles contract
What is the bundle of His?
A group of muscle fibres responsible for conducting the waves of electrical activity between the ventricles to the apex of the heart
What is the Purkyne tissue?
Finer muscle fibres in the right and left ventricle walls that the bundle of His splits into
What is the role of the Purkyne tissue?
Carries the waves of electrical activity into the muscular walls of the right and left ventricles, causing them to contract simultaneously from the bottom up
What does the sinoatrial node (SAN) do?
Generates electrical impulses that cause the cardiac muscles to contract
How is the rate at which the SAN fires unconsciously controlled?
By a part of the brain called the medulla oblongata
Why do animals need to alter their heart rate?
To respond to internal stimuli
How are stimuli detected?
By pressure receptors and chemical receptors
Where are baroreceptors (pressure receptors) found?
In the aorta and carotid arteries
